Re: [Luke] FOX, Mojo, ACE, Secondary Inlets
These are just my personal views. I may be in the minority on some of these, and there is no consensus on any of them among experienced jumpers. I’m basing my thoughts on approximately 200 jumps on an unvented FOX (with multi), 150 on a Vtec FOX (with multi), 100 on a Mojo and 100 on a Blackjack.
Vents:
I pretty much only jump vented canopies. There are lots of reasons for this, which I will not go into here.
I would not recommend a vented (or valved) canopy for a beginner. Deep brakes can cause a canopy with bottomskin inlets to backsurge on opening. Shallow brakes can cause any canopy to surge forward on opening. The opening backsurge phenomenon is poorly understood (and unresearched). Most BASE gear manufacturers have taken to covering up that problem (rather than addressing it) by simply lightening the standard brake settings, removing deep brake settings, and not telling anyone about the problem. This means that most new vented canopies will surge forward on opening. Most inexperienced BASE jumpers will not realize this, and will not know (because the manufacturers, by and large, are not telling them) that they need to customize their brake settings. Kudoz to Morpheus/Atair, the only manufacturer I know of that is trying to address, rather than hide, this issue.
Uncovered secondary inlets (vents) also degrade glide angle and flare power. Valved inlets preserve these characteristics.
In my opinion, secondary (bottom skin) inlets are suitable only for experienced jumpers. I love my Blackjack, and I’m very happy with my Vtec FOX, but I wouldn’t put someone off for their first jumps on either canopy.
Multi:
I am not convinced that the multi has any real effect on deployment. Roughly half my jumps have been on multi-equipped canopies, and I honestly can’t tell the difference. Since the multi adds both cost and complexity to the BASE system, I wouldn’t bother with it, for either beginner or advanced jumpers.
FOX
The FOX is a proven performer. It is solid, easy to pack and can take tons of abuse (mine has 14 patches, and around 50 water landings—and I still jump it). However, the slider down openings of an unvented FOX are somewhat inconsistent. I have found that the canopy reaches bottom skin expansion (initial pressurization) at about the same rate as other canopies, but then lags behind in cell inflation (full pressurization). This makes it slower to initial riser response than either the Mojo or Ace. The same design characteristic (shallow angle of attack) that creates this pressurization issue (and gives it a very good glide angle), makes the FOX “mushy” in deep brakes. The stall point is earlier in the riser stroke than a Mojo, Troll, or Ace, and the canopy has difficulty with steep, braked approaches. Note that the FOX’s issues are very well addressed by adding secondary inlets (vents or valves), but that (see above) I do not recommend secondary inlets for a beginner.
I think the standard FOX is pretty much done. I think the Vtec FOX is a good canopy for an experienced, conservative jumper. I wouldn’t recommend either for a beginner.
Mojo
The Mojo is also a well proven canopy. It has a steeper angle of attack than the FOX, and hence shorter time to full pressurization. This also means that it has superior deep braked approaches, but less glide angle and a weaker flare than the standard FOX (but better than the Vtec FOX).
I wouldn’t be doing any cutting edge BASE on a Mojo (I’m old already—I can hear a lisping Aussie saying “back in the day, we use to do 175 foot freefalls on standard Mojos!”). But, I think it’s a great canopy for a beginner to bang out their first 100 or so jumps on. And, they’re pretty easy to find used (and cheap).
Ace
The Ace is hands down better than the Mojo. It has a wider control range, flying both faster (and with much better glide) and slower (and steeper) than either the FOX or Mojo. This added flight range is a great help in hitting landing areas. Additionally, it pressurizes cleaner and more consistently than either of the earlier canopies. This is partly due to a steep angle of attack, but mostly due to changes in the actual wing profile (kudos to Consolidated Rigging and Atair, for realizing that the first step in designing a new wing ought to be to look at the actual airfoil). While the Ace’s pressurization is not as clean as a canopy with secondary inlets, it is far better than any un-vented canopy I’ve seen.
The Ace is the highest performance BASE airfoil I’ve jumped. This has big advantages if you take the time to learn to fly it. It can sink extremely well (perhaps a touch worse than the Troll, but better than anything else), and is super-responsive to control (either riser or toggle) input. This can be dangerous if you don’t learn to fly it (or are uncurrent on it). I believe that appropriate riser pressure is more important on the Ace than previous canopies. If you yard on a riser, you spin around . This means that you also lose altitude fast. If you are not aware of this, you can sink yourself into real trouble in a hurry. But if you know the canopy, and fly it well, this responsiveness is a tremendous asset.
My vote would be for a used Mojo over that vented FOX. If you’re feeling rich enough for new, I’d go for the Ace.
All right, enough rambling.
Tom Aiello
Tom@SnakeRiverBASE.com
Snake River BASE Academy
